Plasma from Patients with Rheumatoid Arthritis Reduces Nitric Oxide Synthesis and Induces Reactive Oxygen Species in A Cell-Based Biosensor.

Rheumatoid arthritis (RA) has been associated with a higher risk of developing cardiovascular (CV) diseases. It has been proposed that systemic inflammation plays a key role in premature atherosclerosis development, and is therefore crucial to determine whether systemic components from RA patients promotes endothelial cell-oxidative stress by affecting reactive oxygen species (ROS) and nitric-oxide (NO) production. The aim of this study was to evaluate whether plasma from RA patients impair NO synthesis and ROS production by using the cell-line ECV-304 as a biosensor. NO synthesis and ROS production were measured in cells incubated with plasma from 73 RA patients and 52 healthy volunteers by fluorimetry. In addition, traditional CV risk factors, inflammatory molecules and disease activity parameters were measured. Cells incubated with plasma from RA patients exhibited reduced NO synthesis and increased ROS production compared to healthy volunteers. Furthermore, the imbalance between NO synthesis and ROS generation in RA patients was not associated with traditional CV risk factors. Our data suggest that ECV-304 cells can be used as a biosensor of systemic inflammation-induced endothelial cell-oxidative stress. We propose that both NO and ROS production are potential biomarkers aimed at improving the current assessment of CV risk in RA.

Effect of Systemic Inflammation on the Function of Insulin and Glucose Metabolism in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a systemic autoimmune disease of unknown etiology characterized by chronic inflammation of the synovial membranes and articular structures of the joints. The concomitant comorbidities are important in the management and treatment of patients with RA, because they decrease their life quality and expectancy - with cardiovascular diseases being the most common comorbidities and primary cause of death in RA. Traditional cardiovascular risk factors, such as diabetes mellitus (DM) and insulin resistance (IR) are prevalent in these patients. The prevalence of DM in RA patients has not been well established and the association between these diseases is controversial. On the other hand, several epidemiological studies support the association between RA and IR, with the latter being linked to systemic inflammatory markers, including C reactive protein and erythrocyte sedimentation rate. Patients with RA who underwent glucocorticoid therapy were also determined to have a defective insulin sensitivity and pancreatic ß-cell dysfunction. It has been proposed that systemic inflammation due to RA may result in insulin resistance - moreover, studies have examined the effect of inflammatory cytokines such as TNF-α, IL-6 and IL-1 on insulin sensitivity and glucose metabolism. Likewise, the association between RA and IR, and its role on the different characteristics of the disease, such as duration, activity, and treatment with glucocorticoids has not been well defined. A gap in the current understanding regarding the role that the systemic inflammation and the different RA characteristics have on the insulin function and glucose metabolism of RA patients suggest that more studies are required to elucidate these mechanisms.